Olympus IR-500 Reference Manual page 180

Using various clock functions from the clock menu
4
Press d to enter the volume level settings.
Press a/c to select the desired volume level.
ALARM SOUND
1
2
3
CANCEL SELECT
5
Press 9.
The selected alarm sound and volume level are set. Press p to return to clock mode.
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LOW
MID
HIGH
GRADUAL
GO